The present invention relates to a new and improved construction of a weft thread-storage apparatus for a loom, especially a gripper loom.
Generally speaking, the invention relates to a weft thread-storage apparatus for a loom, especially a gripper loom, comprising a storage which can be connected with a suction air source. At the one end face or side of the storage there extends practically over the entire width thereof an opening of substantially slot-shaped configuration. The storage serves for the temporary, loop-shaped storing of a weft or filling thread which is to be inserted into the weaving shed, and comprises a central loop divider for laying mutually parallely extending partial thread loops.
With looms, especially gripper looms when confronted with increasing weaving widths there exists the problem of preparing at a given depth of the storage a sufficient thread length for the weft or filling which is to be inserted. Such problems are aggravated by the tendency of increasing the weft insertion frequency, and therefore, the need for higher storage operating cycles or frequencies.
While there are already known constructions of storage apparatuses which are capable of storing sufficient thread lengths, such constructions require an enormous amount of space and/or complicated mechanisms with relatively high moments of inertia. Thus, these state-of-the-art storage apparatuses are unsuitable for solving the aforementioned problems.
There is known, for instance, from French Pat. No. 2,153,185 and Swiss Pat. No. 441,151 a storage which is divided into several separate channels by means of loop dividers. According to the aforementioned Swiss Pat. No. 441,151, for instance, there is successively threaded or looped into these separate channels a portion of the weft thread by alternatingly opening and closing valves which are arranged at the air suction openings.
It will be readily appreciated that with these prior art proposals there is required a relatively high constructional and circuit expenditure, especially with respect to the valve means.
In German Pat. No. 2,164,891 there furthermore is disclosed an apparatus for preparing predetermined thread lengths at a jet-weaving machine. Here, the storage equally is divided into separate chambers or compartments by wall means. The thread infeed to each chamber or compartment is performed by adjusting or positioning a thread infeed tube for looping the thread into the chamber, while simultaneously actuating or switching air suction valves and the thread clamps at the individual transfer locations. With this prior art design air suction valves are equally required for each chamber or compartment.
This arrangement is equally complicated and expensive and incapable of satisfying present day requirements.